Publications
Cluster Computing for Embedded/Real-Time Systems
January 1, 2000
Book Chapter
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Cluster Computing White Paper
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Summary
Cluster computing is not a new area of computing. It is, however, evident that there is agrowing interest in its usage in all areas where applications have traditionally used parallelor distributed computing platforms. The mounting interest has been fuelled in part by theavailability of powerful microprocessors and high-speed networks as off-the-shelf commoditycomponents as well as in part by the rapidly maturing software components available tosupport high performance and high availability applications.This rising interest in clusters led to the formation of an IEEE Computer Society Task Forceon Cluster Computing (TFCC1) in early 1999. An objective of the TFCC was to act both as amagnet and a focal point for all cluster computing related activities. As such, an earlyactivity that was deemed necessary was to produce a White Paper on cluster computing andits related technologies.Generally a White Paper is looked upon as a statement of policy on a particular subject. Theaim of this White Paper is to provide a relatively unbiased report on the existing, new andemerging technologies as well as the surrounding infrastructure deemed important to thecluster computing community. This White Paper is essentially a snapshot of cluster-relatedtechnologies and applications in year 2000.This White Paper provides an authoritative review of all the hardware and softwaretechnologies that can be used to make up a cluster now or in the near future. Thesetechnologies range from the network level, through the operating system and middlewarelevels up to the application and tools level. The White Paper also tackles the increasinglyimportant areas of High Availability and Embedded/Real Time applications, which are bothconsidered crucial areas for future clusters.The White Paper has been broken down into twelve chapters, each of which has been puttogether by academics and industrial researchers who are both experts in their fields andwhere willing to volunteer their time and effort to put together this White Paper.On a personal note, I would like to thank all the contributing authors for finding the time toput the effort into their chapters and making the overall paper an excellent state-of-the-artreview of clusters. In addition, I would like to thank the reviewers for their timely comments.
Summary
Cluster computing is not a new area of computing. It is, however, evident that there is agrowing interest in its usage in all areas where applications have traditionally used parallelor distributed computing platforms. The mounting interest has been fuelled in part by theavailability of powerful microprocessors and high-speed networks as...
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Lincoln Laboratory Evaluation of TCAS II Logic Version 7 Appendices Volume II
December 13, 1999
Project Report
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MIT Lincoln Laboratory Report ATC-268,II
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Volume I described the analysis procedures and inputs. This volume presents tables and figures that were generated during the assessment to the TCAS Logic Performance.
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Volume I described the analysis procedures and inputs. This volume presents tables and figures that were generated during the assessment to the TCAS Logic Performance.
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Lincoln Laboratory Evaluation of TCAS II Logic Version 7 Volume I
December 13, 1999
Project Report
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MIT Lincoln Laboratory Report ATC-268,I
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This report documents the Lincoln Laboratory evaluation of the Traffic Alert and Collision Avoidance System II (TCAS II) logic version 7. TCAS II is an airborne collision avoidance system required since 30 December 1993 by the FAA on all air carrier aircraft with more than 30 passenger seats operating in the U.S. airspace. Version 7 is a major revision to the TCAS II logic consisting of more than 300 separately defined changes affecting all majot TCAS areas (surveillance, CAS logic and displays/aurals). Lincoln Laboratory Evaluated the logic by examining approximately two million simulated pairwise TCAS-TCAS encounters, derived from actual tracks recorded in U.S. airspace. The main goals of the evaluation were: (1) to study the performance of the new TCAS-TCAS coordinated reversal logic; (2) to detect and explain any areas of performance; (3) to examine the performance of the version 7 logic for the 30 Representative NMACs identified during the 6.04a logic evaluation; and (4) to understand the limitations of the logic by analyzing every version NMAC. Five Lincoln Laboratory analysis programs written for previous logic evaluation work were updated and new software was written to aid in the evaluation of TCAS-TCAS sense reversals. There were four phases of the evaluation corresponding to the above goals. For each phase the report gives an overview of the evaluation approach taken and a description of the results. An overall summary and perspective on the evolution of the TCAS II logic are given at the end of the report.
Summary
This report documents the Lincoln Laboratory evaluation of the Traffic Alert and Collision Avoidance System II (TCAS II) logic version 7. TCAS II is an airborne collision avoidance system required since 30 December 1993 by the FAA on all air carrier aircraft with more than 30 passenger seats operating in...
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The Vector, Signal, and Image Processing Library (VSIPL): an Open Standard for Astronomical Data Processing
December 1, 1999
Abstract
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Bulletin of the American Astronomical Society, Vol. 31, p.1497
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The Vector/Signal/Image Processing Library (VSIPL) is a DARPA initiated effort made up of industry, government and academic representatives who have defined an industry standard API for vector, signal, and image processing primitives for real-time signal processing on high performance systems. VSIPL supports a wide range of data types (int, float, complex, ...) and layouts (vectors, matrices and tensors) and is ideal for astronomical data processing. The VSIPL API is intended to serve as an open, vendor-neutral, industry standard interface. The object-based VSIPL API abstracts the memory architecture of the underlying machine by using the concept of memory blocks and views. Early experiments with VSIPL code conversions have been carried out by the High Performance Computing Program team at the UCSD. Commercially, several major vendors of signal processors are actively developing implementations. VSIPL has also been explicitly required as part of a recent Rome Labs teraflop procurement. This poster presents the VSIPL API, its functionality and the status of various implementations.
Summary
The Vector/Signal/Image Processing Library (VSIPL) is a DARPA initiated effort made up of industry, government and academic representatives who have defined an industry standard API for vector, signal, and image processing primitives for real-time signal processing on high performance systems. VSIPL supports a wide range of data types (int, float...
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Weather sensing and data fusion to improve safety and reduce delays at major west coast airports
November 30, 1999
Project Report
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MIT Lincoln Laboratory Report ATC-290
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The objective of this study was to analyze the weather sensing and data fusion required to improve safety and reduce delays at a number of west coast airports that are not currently scheduled to receive an Integrated Terminal Weather System (ITWS). This report considers the Los Angeles (LAX), San Francisco (SFO), Seattle (SEA) and Portland, OR (PDX) international airports. A number of visits were made to the various ATC facilities to better understand their weather decision support operational needs. Analyses were made of an incident of lightning strikes to two aircraft at SEA in February 1999, and a prototype terminal winds product was developed for LAX that uses profilers as well as plane reports to update the the National Weather Service (NWS) Rapid Update Cycle (RUC) winds estimates. We found that an augmented ITWS could potentially address safety concerns for triggered lightning strikes and vertical wind shear in winter storms at Portland and Seattle. An augmented ITWS terminal winds product (that uses wind profiler data in addition to the current ITWS sensors) could provide very large delay reductions for LAX and SFO during winter storms as a component of a wake vortex advisory system. This augmented product also could provide significant delay reduction benefits at SEA. The sensors required to obtain the projected benefits at SFO do not exist currently. Portland may warrant additional sensors to address the vertical wind shear problems, and LAX would require additional sensors for a wake vortex advisory system. We recommend near-term experimental measurements at PDX to determine the optimum sensor mix and that an operational evaluation of the prototype augmented ITWS terminal winds product be carried out at LAX to determine if the current sensor mix can meet operational needs. Lightning strike data at SEA and PDX should be analyzed to determine if a proposed triggered lightning predictant is accurate.
Summary
The objective of this study was to analyze the weather sensing and data fusion required to improve safety and reduce delays at a number of west coast airports that are not currently scheduled to receive an Integrated Terminal Weather System (ITWS). This report considers the Los Angeles (LAX), San Francisco...
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Estimation of modulation based on FM-to-AM transduction: two-sinusoid case
November 1, 1999
Journal Article
Published in:
IEEE Trans. Signal Process., Vol. 47, No. 11, November 1999, pp. 3084-3097.
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A method is described for estimating the amplitude modulation (AM) and the frequency modulation (FM) of the components of a signal that consists of two AM-FM sinusoids. The approach is based on the transduction of FM to AM that occurs whenever a signal of varying frequency passes through a filter with a nonflat frequency response. The objective is to separate the AM and FM of the sinusoids from the amplitude envelopes of the output of two transduction filters, where the AM and FM are nonlinearly combined in the amplitude envelopes. A current scheme is first refined for AM-FM estimation of a single AM-FM sinusoid by iteratively inverting the AM and FM estimates to reduce error introduced in transduction. The transduction filter pair is designed relying on both a time-and frequency-domain characterization of transduction error. The approach is then extended to the case of two AM-FM sinusoids by essentially reducing the problem to two single-component AM-FM estimation problems. By exploiting the beating in the amplitude envelope of each filter output due to the two-sinusoidal input, a closed-form solution is obtained. This solution is also improved upon by iterative refinement. The AM-FM estimation methods are evaluated through an error analysis and are illustrated for a wide range of AM-FM signals.
Summary
A method is described for estimating the amplitude modulation (AM) and the frequency modulation (FM) of the components of a signal that consists of two AM-FM sinusoids. The approach is based on the transduction of FM to AM that occurs whenever a signal of varying frequency passes through a filter...
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Shunting networks for multi-band AM-FM decomposition
October 17, 1999
Conference Paper
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Proc. IEEE Workshop on Applications of Signal Processing to Audio and Acoustics, 17-20 October 1999.
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We describe a transduction-based, neurodynamic approach to estimating the amplitude-modulated (AM) and frequency-modulated (FM) components of a signal. We show that the transduction approach can be realized as a bank of constant-Q bandpass filters followed by envelope detectors and shunting neural networks, and the resulting dynamical system is capable of robust AM-FM estimation. Our model is consistent with recent psychophysical experiments that indicate AM and FM components of acoustic signals may be transformed into a common neural code in the brain stem via FM-to-AM transduction. The shunting network for AM-FM decomposition is followed by a contrast enhancement shunting network that provides a mechanism for robustly selecting auditory filter channels as the FM of an input stimulus sweeps across the multiple filters. The AM-FM output of the shunting networks may provide a robust feature representation and is being considered for applications in signal recognition and multi-component decomposition problems.
Summary
We describe a transduction-based, neurodynamic approach to estimating the amplitude-modulated (AM) and frequency-modulated (FM) components of a signal. We show that the transduction approach can be realized as a bank of constant-Q bandpass filters followed by envelope detectors and shunting neural networks, and the resulting dynamical system is capable of...
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A comparative study of existing and proposed FAA and Eurocontrol CHIs for en route air traffic control
September 26, 1999
Conference Paper
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44th Annual Air Traffic Control Association Conf. Proc., 26-30 September 1999, pp. 22-26.
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In this paper we present a comparison of the Computer Human Interface (CHI) similarities and differences among the key Free Flight Phase 1 (FFP1) products for en route air traffic control (ATC) and air traffic control management (ATM) as well as some recent Eurocontrol-based CHI innovations. Our comparative study focuses on details of these disparate CHIs and the potential introduction of advanced graphical interactive features seen in the Eurocontrol CHI. Active US controllers who participated in Eurocontrol's Operational Display and Input Development (ODID) study have requested that the FAA develop an alternative CHI based on ODID and its successors such as the Denmark Sweden Interface (DSI). MIT Lincoln Laboratory has built a CHI Requirements Engineering Model (CREM) to support testing of an alternative ODID-like CHI that is feasible given the newly deployed Display System Replacement (DSR).
Summary
In this paper we present a comparison of the Computer Human Interface (CHI) similarities and differences among the key Free Flight Phase 1 (FFP1) products for en route air traffic control (ATC) and air traffic control management (ATM) as well as some recent Eurocontrol-based CHI innovations. Our comparative study focuses...
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An evaluation of the ASR-9 weather channel based on observations from the ITWS prototypes
September 23, 1999
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-270
Summary
The Federal Aviation Administration's (FAA) Airport Surveillance Radar (ASR-9) is a high-scan-rate system which provides a "critical" function in terms of air traffic control (ATC). In addition to its primary role of air traffic surveillance, the system also generates precipitation data for display on air traffic specialists' radar scopes and for use by automated systems such as the Integrated Terminal Weather System (ITWS) and Weather Systems Processor (WSP). Air traffic managers use these data to provide optimum routes for aircraft operating in and near the Terminal Radar Approach Control (TRACON) airspace. The primary advantage of the ASR-9 - as an aviation weather radar - over either the Terminal Doppler Weather Radar (TDWR) or the Next Generation Weather Radar (NEXRAD) is the rapid update rate, i.e., 30 seconds, which provides air traffic managers with a more accurate representation of weather echo location within the sensor's domain. This is far superior toeither the TDWR or NEXRAD, which takes from 2.5 to 6 minutes to create a volume scan, depending on the scan strategy. The sensor is also quite reliable, with limited down time. An analysis of ASR-9 data from the ITWS prototypes has uncovered a number of problems, which impact the quality of the precipitation data. The data quality issues discussed are overly aggressive ground clutter suppression, polarization mode issues, hardware failures associated with high beandlow beam switching, attenuatiodsignal depolarization, beam-filling losses, bright- band contamination, distant weather contamination, calibration issues, and radadantenna failures. The recommendations to address the ASR-9 data quality issues can be grouped into three categories: "Variable Site Parameter (VSP)" adjustments, hardware component maintenance checks, and automated flagging of data quality problems. The report includes discussion of the frequency and characteristics of each degradation, presenting both hardware and non- hardware related problems, and concludes with proposed solutions to the problems and recommendations designed to improve the overall utility of the ASR-9 precipitation data.
Summary
The Federal Aviation Administration's (FAA) Airport Surveillance Radar (ASR-9) is a high-scan-rate system which provides a "critical" function in terms of air traffic control (ATC). In addition to its primary role of air traffic surveillance, the system also generates precipitation data for display on air traffic specialists' radar scopes and...
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Operational and spectrum tests for ATIDS at Dallas/Fort Worth Airport
September 20, 1999
Project Report
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MIT Lincoln Laboratory Report ATC-272
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Runway Incursion (RI) prevention is on the National Transportation Safety Board's (NTSB) list of "10 Most Wanted" safety improvements. Improved surveillance on the airport surface is an important ingredient in that it improves situational awareness and improves the accuracy of tracks used by automation algorithms. Towards this goal, the Runway Incursion Reduction Program (RIRP) has been developing the Airport Target Identification System (ATIDS). ATIDS is a prototype multilateration and Automatic Dependent Surveillance - Broadcast (ADS-B) system. It requires the enabling of existing transponders on the airport surface....The RIRP team, which includes the FAA Volpe National Transportation Systems Center, Massachusetts Institute of Technology Lincoln Laboratory (MIT/LL) and Trios Associates, Inc., has conducted interferences tests at Dallas/Fort Worth Airport (DFW) to quantify the impact that ATIDS would have on that high-use environment. The tests included environmental 1040/1090 MHz measurements, ATCRBS false target investigations, and Mode S interrogation tests. This document reports the results of these tests. [Not complete].
Summary
Runway Incursion (RI) prevention is on the National Transportation Safety Board's (NTSB) list of "10 Most Wanted" safety improvements. Improved surveillance on the airport surface is an important ingredient in that it improves situational awareness and improves the accuracy of tracks used by automation algorithms. Towards this goal, the Runway...
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